urbackup_backend/cryptoplugin/ECDHKeyExchange.cpp
2018-09-09 20:23:24 +02:00

60 lines
2.0 KiB
C++

/*************************************************************************
* UrBackup - Client/Server backup system
* Copyright (C) 2011-2016 Martin Raiber
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
**************************************************************************/
#include "ECDHKeyExchange.h"
#include "../Interface/Server.h"
using namespace CryptoPPCompat;
ECDHKeyExchange::ECDHKeyExchange()
{
CryptoPP::ECDH< CryptoPP::EC2N >::Domain ecdh(CryptoPP::ASN1::sect233k1());
CryptoPP::AutoSeededRandomPool rng;
priv.resize(ecdh.PrivateKeyLength());
pub.resize(ecdh.PublicKeyLength());
ecdh.GenerateKeyPair(rng, priv, pub);
}
std::string ECDHKeyExchange::getPublicKey()
{
return std::string(pub.BytePtr(), pub.BytePtr() + pub.size());
}
std::string ECDHKeyExchange::getSharedKey( const std::string& other_public )
{
CryptoPP::ECDH< CryptoPP::EC2N >::Domain ecdh(CryptoPP::ASN1::sect233k1());
if(other_public.size()!=ecdh.PublicKeyLength())
{
Server->Log("Public key length does not match", LL_ERROR);
return std::string();
}
std::string ret;
ret.resize(ecdh.AgreedValueLength());
if(!ecdh.Agree(reinterpret_cast<byte*>(&ret[0]), priv, reinterpret_cast<const byte*>(other_public.data())))
{
Server->Log("Failed to agree to ECDH shared secret", LL_ERROR);
return std::string();
}
return ret;
}